Is it expensive on an absolute basis or on a relative basis? If getting a metal tube to fly through the air at 500 mph is expensive, then we shouldn't expect that you get a luxury experience just because the ticket price is $200 or whatever.
Also, I checked on google flights and a 2 hour flight is roughly equal to an 11 hour drive. Even if you factor in arriving 3 hours early for departure and 1 hour to get to your final destination, the time savings alone is worth most of the cost of the trip. If you factor in gas/wear on your car it's a no-brainer, even if it's "expensive".
[1] Chicago to washington DC
[2] $200 round trip, $100 for one way, 5 hours * $15/hour = $75